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115-400: In sheep, BTV causes an acute disease with high morbidity and mortality. BTV also infects goats, cattle, and other domestic animals, as well as wild ruminants (for example, blesbuck , white-tailed deer , elk , and pronghorn antelope ). Major signs are high fever, excessive salivation , swelling of the face and tongue, and cyanosis of the tongue. Swelling of the lips and tongue gives

230-677: A clade sister to Cervidae . According to the study, Cervidae diverged from the Bovidae-Moschidae clade 27 to 28 million years ago. The following cladogram is based on a large-scale genome ruminant genome sequence study from 2019: Tragulidae [REDACTED] Antilocapridae [REDACTED] Giraffidae [REDACTED] Cervidae [REDACTED] Bovidae [REDACTED] Moschidae [REDACTED] Hofmann and Stewart divided ruminants into three major categories based on their feed type and feeding habits: concentrate selectors, intermediate types, and grass/roughage eaters, with

345-447: A global warming potential of 86 compared to CO 2 over a 20-year period. As a by-product of consuming cellulose, cattle belch out methane, there-by returning that carbon sequestered by plants back into the atmosphere. After about 10 to 12 years, that methane is broken down and converted back to CO 2 . Once converted to CO 2 , plants can again perform photosynthesis and fix that carbon back into cellulose. From here, cattle can eat

460-431: A lipid envelope. The particle has a diameter of 86 nm. The structure of the 70 nm core was determined in 1998 and was at the time the largest atomic structure to be solved. The two outer capsid proteins, VP2 and VP5, mediate attachment and penetration of BTV into the target cell. VP2 and VP5 are the primary antigenic targets for antibody targeting by the host immune system. The virus makes initial contact with

575-430: A Family of specialized blood feeding flies with a reproductive cycle similar that described for tsetse-flies. They are often known as louse-flies because some species either shed their wings when as adults they find a host after active flying (in genus Lipoptena ). Alternatively flies of genus Melophagus are so adapted to parasitism that the adults never develop wings. Louse-flies without wings may appear like ticks, but

690-530: A boil) myiasis in the skin of their hosts. The larvae infest these sites when transported there accidentally by blood feeding mosquitoes; the adult female Dermatobia flies lay their eggs on the legs of mosquitoes, a dispersal mechanism called phoresy. Obligate myiasis of various forms are typical of the oestrid genera. Larval Dermatobia torsalo-flies infest the skin and underlying tissues of cattle causing distress, reduced gain in weight and damage to skins used for leather. Larval Gasterophilus stomach-bots infest

805-399: A complete metamorphosis. The females lay eggs with high selectivity on their special hosts and at specific sites there. For example, eggs laid on the legs of horses in the case of species of Gasterophilus . The horse licks at the irritated skin and the larvae transfer to the mouth of horse. The larvae penetrate tissues in the oral cavity, feed parasitically whilst migrating through tissue of

920-1046: A contaminative route on their mouthparts used for sponging up wet nutritious secretions on skin of vertebrate animals. Usually the mechanical transmission of microbes by flies does not involve any developmental stage of the microorganism in the fly. However, some brachyceran flies, such as a group of species of genus Glossina , are important biological transmitters, not mechanical. Typical genera are Tabanus , Haematopota , Chrysops and Hybromitra , also many other genera of importance to domestic animals in some regions of world, tropical and subtropical South America especially. These are large robust flies with massive eyes that often show colored patterns. Antennae are characteristic with three dissimilar segments projecting forward from head. Wings are large and strong with complex venation, and often with complex patterns of brown on clear background. These flies are adapted to hunt widely for their hosts during daytime. Females take repeated small blood meals from their hosts to support development of

1035-487: A cow. The role of saliva is to provide ample fluid for rumen fermentation and to act as a buffering agent. Rumen fermentation produces large amounts of organic acids, thus maintaining the appropriate pH of rumen fluids is a critical factor in rumen fermentation. After digesta passes through the rumen, the omasum absorbs excess fluid so that digestive enzymes and acid in the abomasum are not diluted. Tannins are phenolic compounds that are commonly found in plants. Found in

1150-636: A deep groove between the eyes; the outermost segment of each antenna bears a feather like structure, the arista, which projects forwards. Species within Musca , Hydrotaea , and similar genera have mouthparts adapted for sponging nutritious liquids with their labellar lobes (see photograph of Calliphora mouthparts which also have this sponge structure). Some species of this type, such as Musca vestustissima (Australian bush-fly) also have, as part of this sponge structure, small teeth that can scrape at host's skin down to superficial capillaries to feed on blood. Cattle are

1265-487: A developing larva. The life-cycle is the larviparous type, similar to that of tsetse-flies, few offspring are produced per female but their survival rate is high. In species that never develop wings as adults, such as Melophagus ovinus , the sheep-ked, the fully developed larvae are deposited by the female on the hair coat of the host. There pupation occurs rapidly followed by complete metamorphosis into an adult (see photograph of Melophagus ). Irritation and biting-stress

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1380-414: A large batch of eggs. Eggs are laid on wet soil where larvae develop, sometimes over one or two years by feeding on soil organisms. Males do not feed on blood. Hosts of females include all species of mammalian livestock animals and horses. Tabanid flies have large mouthparts comprising three pairs of cutting / slashing elements that pierce skin in a superficial wound. Blood flowing from this is imbibed through

1495-524: A life cycle and veterinary and medical importance justifying a separate Family designation. Tsetse-flies are found only in sub-Saharan Africa. These flies are closely similar to Stomoxys and Haematobia , but are larger and of a paler brown color. Tsetse-flies of both sexes are robust fliers adapted for hunting their hosts during daytime. Male adults support their mating activity with repeated meals of blood from cattle and similar wild bovid hosts, also wild pigs and warthogs are favored. Life-cycle of tsetse-fly

1610-413: A liquid that smells like the rotting flesh of a carcass and the structure of the trap is designed to prevent the flies from escaping once attracted in. Horse-flies can be controlled by traps that attract the flies to a suspended black ball that mimics a potential host; flies attracted become trapped in a cone above. For area-wide control of tsetse-flies targets (these do not trap the flies) that combine

1725-992: A protective labium (see photograph of Aedes female engorged with blood). Adult females lay eggs in batches on surfaces of stagnant water. Larvae feed on microorganisms and organic detritus in water. Pupation occurs at the surface of the water. Feeding by females is on a wide variety of mammals and birds, whilst males feed on plant sugars. Biting stress can be severe in varied climatic regions (cold northern or tropics) or conditions of much surface water available for breeding where populations of mosquitoes can become dense. Species of genera Aedes , Anopheles and Psorophora transmit equine encephalitis viruses to horses. Culex , Aedes , and Anopheles species of mosquitoes transmit Plasmodium protozoa that cause types of malaria in birds. Culex mosquitoes transmit West Nile virus between birds and horses; they transmit Rift Valley fever virus to livestock species and humans. The nematode worm Dirofilaria immitis that causes heartworm disease in dogs

1840-674: A protective puparium. A new adult emerges from the puparium after a complete metamorphosis. This is known as larviparous reproduction, with the advantage of high survival rate of offspring, but few offspring are produced by each female. Bites from tsetse flies are painful but these flies are not generally associated with direct causes of lost production in cattle. Glossina morsitans and G.pallidipes tsetse-flies are transmitters of various species of Trypanosoma protozoa causing animal trypanosomiasis (= nagana) in cattle, and other forms of trypanosomiasis in sheep, goats, pigs, camels and horses. Tsetse-flies are also notorious as transmitters of

1955-545: A rectangle of dark blue or black cloth and often an attractant chemical act as simple mimics of the fly's host. When the flies land on the cloth they contact the synthetic pyrethroid that is impregnated into the cloth. This technique was used to eradicate Cochliomyia hominivorax screw-worm fly from the USA where the flies were endemic, and from Libya where there had been an accidental importation from South America. Although this species of blowfly under natural conditions has larvae of

2070-730: A serious threat in Scandinavia and Switzerland and the first outbreak in Denmark was reported. In autumn 2008, several cases were reported in the southern Swedish provinces of Småland, Halland, and Skåne, as well as in areas of the Netherlands bordering Germany, prompting veterinary authorities in Germany to intensify controls. Norway had its first finding in February 2009, when cows at two farms in Vest-Agder in

2185-415: A simple single-chambered stomach. Being hindgut fermenters , these animals ferment cellulose in an enlarged cecum . In smaller hindgut fermenters of the order Lagomorpha (rabbits, hares, and pikas), and Caviomorph rodents ( Guinea pigs , capybaras , etc.), material from the cecum is formed into cecotropes , passed through the large intestine, expelled and subsequently reingested to absorb nutrients in

2300-431: A small wound. The larvae hatch and rapidly invade the superficial layers of skin to continue feeding there until ready to pupate. This form of parasitism is essential for these types of fly, and causes obligate myiasis (obligate = necessary or essential). This infestation develops into severe disease and can be fatal if the infestation is at a vulnerable site such as ear or navel of the host. Adult blow-flies such as those in

2415-444: A sponge-like element of the mouthparts, the labella (similar to that shown in photograph of Calliphora ). Bites of tabanid flies are painful. Dense populations of these flies cause severe biting stress to livestock and horses leading to reduction of gain in liveweight. These hosts may additionally suffer loss of grazing time by clustering in tight defensive packs, a situation known as fly-syndrome. Many genera of tabanid flies transmit

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2530-475: A superficial wound from which blood is imbibed. Lifecycle is similar to that of mosquitoes: female feeds on blood, matures, and lays batch of eggs repeatedly. Males are not blood feeders. The site for larval development is within wet soil and bogs. Hosts of biting midges are wide variety of mammals and birds. Severe biting stress to cattle, sheep and horses is caused. Horses suffer from a cutaneous hypersensitivity reaction called sweet-itch, or Queensland-itch that

2645-511: A superficial wound in skin. Blood flowing into the wound is sponged up by the labella organ of the mouthparts (see photograph of Tabanus mouthparts). The flies tend to take small meals from many hosts at short intervals, to avoid the defensive actions of their hosts. Fresh blood on the labella may contaminate other hosts with pathogenic organisms. Many species of brachyceran flies such as the house-flies and blow-flies that do not feed on blood are also mechanical transmitters of pathogenic organisms by

2760-470: A three-compartment stomach instead of four like ruminants. The Hippopotamidae (comprising hippopotamuses ) are well-known examples. Pseudoruminants, like traditional ruminants, are foregut fermentors and most ruminate or chew cud . However, their anatomy and method of digestion differs significantly from that of a four-chambered ruminant. Monogastric herbivores , such as rhinoceroses , horses , guinea pigs , and rabbits , are not ruminants, as they have

2875-463: A typical host for Musca and similar species of house-flies that are attracted to protein containing liquids at the eyes and nostrils of their hosts. Species within the genera Stomoxys stable-flies, and Haematobia horn-flies are highly adapted for blood feeding, having mouthparts consisting of a strong projecting labium with cutting elements at its point. This is used to pierce deeply into skin of host to access blood (see photograph of Stomoxys in

2990-572: A variety of bacteria involved in mastitis of cattle. The conjunctivitis of cattle known as pink-eye is caused by Moraxella bovis bacteria transmitted by Musca autumnalis face-flies. The feeding of various Musca species of fly permits the contaminative transmission of nematode worms, for example Parafilaria bovicola , causing a nodular filariasis in cattle. Stomoxys species transmit several species of Trypanosoma protozoa to cattle, sheep and goats causing various types of trypanosomiasis. Haematobia horn-flies transmit nematode worms in

3105-503: A vessel owned by Khalifeh Livestock Trading and managed by Talia Shipping Line, both based in Lebanon, has been denied right to dock in Spain, as it has about 895 male calves suspected to be infected by bluetongue disease. African horse sickness is related to bluetongue and is spread by the same midges ( Culicoides species). It can kill the horses it infects and mortality may go as high as 90% of

3220-461: A warm, moist, anaerobic environment with a temperature range of 37.7 to 42.2 °C (99.9 to 108.0 °F) and a pH between 6.0 and 6.4. Without the help of microbes, ruminants would not be able to use nutrients from forages. The food is mixed with saliva and separates into layers of solid and liquid material. Solids clump together to form the cud or bolus . The cud is then regurgitated and chewed to completely mix it with saliva and to break down

3335-618: A wide range of climates (from tropic to arctic) and habitats (from open plains to forests). The population of domestic ruminants is greater than 3.5 billion, with cattle, sheep, and goats accounting for about 95% of the total population. Goats were domesticated in the Near East circa 8000 BC. Most other species were domesticated by 2500 BC., either in the Near East or southern Asia. Ruminating animals have various physiological features that enable them to survive in nature. One feature of ruminants

3450-570: Is a stem-based definition for Ruminantiamorpha, and is more inclusive than the crown group Ruminantia. As a crown group, Ruminantia only includes the last common ancestor of all extant (living) ruminants and their descendants (living or extinct ), whereas Ruminantiamorpha, as a stem group, also includes more basal extinct ruminant ancestors that are more closely related to living ruminants than to other members of Artiodactyla. When considering only living taxa ( neontology ), this makes Ruminantiamorpha and Ruminantia synonymous , and only Ruminantia

3565-785: Is a complete metamorphosis with larvae that are nonparasitic, living in environments such as pools of water, soil, and streams. A complete metamorphosis is illustrated by the photograph of Stomoxys eggs, larvae, and adult ( Stomoxys are in suborder Brachycera). Only females feed on blood, taking a large meal to support production of several hundred eggs, followed by several more cycles of blood meal followed by egg laying. Males feed on plant nectar and similar sources of sugars. Nematocerans are very important as transmitters of viruses, protozoa, and nematode worms. Also, they are often important for biting stress when in large numbers, and may cause allergic reactions at their feeding sites. A typical pathway of transmission of organisms by blood-feeding flies

Bluetongue disease - Misplaced Pages Continue

3680-401: Is a condition in which the brain's cerebral hemispheres are like swiss cheese, or absent, and replaced by sacs filled with cerebrospinal fluid . Ewes infected with bluetongue virus while pregnant can have lambs with this defect, as well as giving birth to lambs who are small, weak, deformed or blind. These affected lambs die within a few days of birth, or are born dead. Bluetongue is caused by

3795-418: Is also used for dipteran flies that are harmless to domestic animals such as those also known as lake-flies ( Chironomidae ). These are small to minute flies (a typical vernacular name is "no-see-ums"). Wings are veined, short, and rounded, usually with distinctive patterns of dark brown on clear backgrounds. Mouthparts are relatively short and complex with three pairs of cutting or slashing elements that create

3910-593: Is caused by antigenic components of saliva of biting midges. Poultry may be severely afflicted with biting stress. Species such as Culicoides imicola and Culicoides variipennis transmit bluetongue virus between sheep and cattle (see diagram and photograph above), and they transmit African horse sickness virus between horses and other equids. Culicoides midges transmit Leucocytozoon protozoa to poultry birds. The important genera are Phlebotomus (distributed in Africa and Eurasia) and Lutzomyia (distributed in

4025-410: Is caused. Damage to skin results in poor quality of leather when hides are processed, a condition known as cockle. Sheep-keds transmit the bacterium Eperythrozoon ovis to sheep and this infection may cause fever and anemia. They also transmit Trypanosoma melophagium , but this protozoan seems non-pathogenic. These usually consist of netting made of synthetic fibers or fine metal mesh that is fitted to

4140-427: Is dorsally humped and dark brown or black (see photograph of Simulium ). Lifecycle is similar to mosquitoes: females lay eggs on plants at surface of streams and rivers; larvae settle onto solid substrate in water and feed on suspended organic detritus; pupation occurs at water surface. Hosts are most livestock species, horses and poultry and many wild animals. Humans also may be severely distressed by blackflies. Feeding

4255-531: Is estimated to contain 10–50 billion bacteria and 1 million protozoa, as well as several yeasts and fungi. Since the environment inside a rumen is anaerobic , most of these microbial species are obligate or facultative anaerobes that can decompose complex plant material, such as cellulose , hemicellulose , starch , and proteins . The hydrolysis of cellulose results in sugars, which are further fermented to acetate, lactate, propionate, butyrate, carbon dioxide, and methane . As bacteria conduct fermentation in

4370-422: Is high in susceptible breeds of sheep. In Africa, local breeds of sheep may have no mortality, but in imported breeds, it may be up to 90%. In cattle, goats, and wild ruminants, infection is usually asymptomatic despite high virus levels in blood. Red deer are an exception, and in them the disease may be as acute as in sheep. Lamb infected in utero can develop congenital hydranencephaly . This abnormality

4485-423: Is highly specialized. Females take repeated small meals of blood to support the development within their abdomen of a single larvae over one period. This will be repeated for as many times as the female is able to survive, depending mostly on availability of hosts. The single larva emerges fully grown from the female, weighing more than the female. Then the larva immediately burrows into dry sandy soil to pupate within

4600-439: Is its survival between midge seasons in temperate regions. Adults of Culicoides are killed by cold winter temperatures, and BTV infections typically do not last for more than 60 days, which is not long enough for BTV to survive until the next spring. It is believed that the virus somehow survives in overwintering midges or animals. Multiple mechanisms have been proposed. A few adult Culicoides midges infected with BTV may survive

4715-514: Is now usually classified as part of the Brachycera . Antennae consist of three relatively short segments with asymmetric shapes. Brachyceran flies are of medium to large size and compact shape. They have large compound eyes, well developed wings, and generally fly during daytime seeking food and mates. Life-cycle is a complete metamorphosis, as for Nematocera. However, in contrast to nematoceran flies which have larvae always non-parasitic and living in

Bluetongue disease - Misplaced Pages Continue

4830-508: Is now usually classified as part of the Brachycera .) Antennae are usually long, with many similar and symmetric segments. These are small to very small flies, usually of delicate morphology with relatively long legs and wings. Body and wings are often covered in fine scales. Thorax is distinctly humped, abdomen is elongated. All species of veterinary and medical importance are blood feeders, with various types of mouthparts (these variations do not relate clearly to dipteran taxonomy). Lifecycle

4945-770: Is replicated via structural protein VP1, an RNA-dependent RNA polymerase. The lack of proof-reading abilities results in high levels of transcription errors, resulting in single nucleotide mutations. Despite this, the BTV genome is quite stable, exhibiting a low rate of variants arising in populations. Evidence suggests this is due to purifying selection across the genome as the virus is transmitted alternately through its insect and animal hosts. However, individual gene segments undergo different selective pressures and some, particularly segments 4 and 5, are subject to positive selection. Genetic diversification of BTV occurs primarily through reassortment of

5060-409: Is shown below as a virus transmitted by an adult fly that feeds repeatedly on several hosts (see diagram for Biological transmission, and photograph of Culicoides ). Insects that transmit pathogenic organisms are commonly known as vectors. The diagram shows what is known as biological transmission (= developmental transmission) because it is necessary for the transmitted organism to develop in the fly to

5175-408: Is the large ruminal storage capacity that gives them the ability to consume feed rapidly and complete the chewing process later. This is known as rumination, which consists of the regurgitation of feed, rechewing, resalivation, and reswallowing. Rumination reduces particle size, which enhances microbial function and allows the digesta to pass more easily through the digestive tract. Vertebrates lack

5290-439: Is their continuously growing teeth. During grazing, the silica content in forage causes abrasion of the teeth. This is compensated for by continuous tooth growth throughout the ruminant's life, as opposed to humans or other nonruminants, whose teeth stop growing after a particular age. Most ruminants do not have upper incisors; instead, they have a thick dental pad to thoroughly chew plant-based food. Another feature of ruminants

5405-434: Is through skin with short complex slashing mouthparts. Severe biting stress when they seasonally swarm near running water. Severe anaphylaxis may develop rapidly in previously sensitized hosts, potentially leading to death of cattle. Simulium black-flies transmit to Leucocytozoon protozoa poultry. They also transmit Onchocerca nematode worms to cattle causing bovine onchocerciasis. The former suborder Cyclorrhapha

5520-529: Is transmitted by species of Culex and Aedes . See photograph of microfilaria stage of Dirofilaria immitus in blood of dog; adult worms in dog's heart grow to several centimeters long. (Mosquitoes are of major importance as transmitters of many types of pathogenic microorganisms to humans causing diseases such as malaria and yellow fever . Plasmodium species causing malaria in humans are exclusively transmitted by Anopheles mosquitoes.) Typical genera are Culicoides and Leptoconops (the term "midge"

5635-912: Is used. Thus, Ruminantiamorpha is only used in the context of paleontology . Accordingly, Spaulding grouped some genera of the extinct family Anthracotheriidae within Ruminantiamorpha (but not in Ruminantia), but placed others within Ruminantiamorpha's sister clade, Cetancodontamorpha . Ruminantia's placement within Artiodactyla can be represented in the following cladogram : Tylopoda (camels) [REDACTED]   Suina (pigs) [REDACTED]   Tragulidae (mouse deer) [REDACTED]   Pecora (horn bearers) [REDACTED]   Hippopotamidae (hippopotamuses) [REDACTED]   Cetacea (whales) [REDACTED] Within Ruminantia,

5750-456: Is very important because it provides liquid for the microbial population, recirculates nitrogen and minerals, and acts as a buffer for the rumen pH. The type of feed the animal consumes affects the amount of saliva that is produced. Though the rumen and reticulum have different names, they have very similar tissue layers and textures, making it difficult to visually separate them. They also perform similar tasks. Together, these chambers are called

5865-872: The Musca , Stomoxys , and Haematobia species have larval habitats amongst livestock dung and soiled bedding found around livestock farms. There is scope for reducing fly infestation by clearing these wastes to composting containers or areas. However, for many types of dipteran flies, the larvae inhabit areas such as bogs ( Culicoides ), swamps (mosquitoes), or rivers ( Simulium ) that are impractical to treat under typical commercial constraints within agriculture. Synthetic chemicals such as diethyltoluamide (often called DEET) dissolved in an oily carrier are sometimes used. Also there are various organic, botanical repellents such as citronella oil and neem oil . Typically various types of synthetic pyrethroids such as deltamethrin, cypermethrin , and permethrin are formulated in an oil or watery suspension suitable for application direct to

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5980-550: The Tragulidae (mouse deer) are considered the most basal family, with the remaining ruminants classified as belonging to the infraorder Pecora . Until the beginning of the 21st century it was understood that the family Moschidae (musk deer) was sister to Cervidae . However, a 2003 phylogenetic study by Alexandre Hassanin (of National Museum of Natural History, France ) and colleagues, based on mitochondrial and nuclear analyses, revealed that Moschidae and Bovidae form

6095-766: The Trypanosoma species causing African trypanosomiasis (= sleeping sickness) in humans. Important genera include Calliphora , Lucilia , Chrysomya , Cochliomyia and Wohlfahrtia . All calliphorid flies are all large, robust, strong day-time fliers. Their antennae are as described above for house-flies and others in the Family Muscidae. Adult flies in family Calliphoridae feed as adults of both sexes mostly on proteinaceous liquids found on surface of decaying animal carcasses and similar material. These liquids are taken in using sponging mouthparts (see photograph of Calliphora ). In genera such as Calliphora and Lucilia

6210-467: The pathogenic virus , Bluetongue virus ( BTV ), of the genus Orbivirus , of the Reoviridae family. Twenty-seven serotypes are now recognised for this virus. The twenty-seven serotypes are the result of the high variability of a single outer capsid protein, VP2. The virus particle consists of 10 strands of double-stranded RNA surrounded by two protein shells. Unlike other arboviruses , BTV lacks

6325-410: The (one's) cud' is to reflect or meditate. In psychology, "rumination" refers to a pattern of thinking, and is unrelated to digestive physiology. Methane is produced by a type of archaea , called methanogens , as described above within the rumen, and this methane is released to the atmosphere. The rumen is the major site of methane production in ruminants. Methane is a strong greenhouse gas with

6440-889: The Americas). The term "sandfly" is often used to refer to various other types of flies. Sandflies are like small versions of mosquitoes, but also with overall furry appearance from many long setae (like hairs) on body and wings (see photograph of Phlebotomus pappatasi ). Mouthparts are medium length. Lifecycle is similar to midges: site for egg laying and larval development is surface of relatively dry soil. Many species of mammals and birds are used as hosts. Females suck blood using medium length complex mouthparts, whilst males feed on plant sugars. Species of Phlebotomus and Lutzomyia sandflies are notorious as transmitters of species of Leishmania protozoa that cause visceral and cutaneous leishmaniasis in domestic animals and also humans. Dogs become infected with Leishmania infantum and L.tropica ;

6555-502: The BTV transcriptase. In addition to the seven structural proteins, three non-structural (NS) proteins, NS1, NS2, NS3 (and a related NS3A) are synthesised in BTV-infected cells. Of these, NS3/NS3A is involved in the egress of the progeny virus. The two remaining non-structural proteins, NS1 and NS2, are produced at high levels in the cytoplasm and are believed to be involved in virus replication, assembly and morphogenesis. The viral genome

6670-543: The Gallery below. Females of these flies typically take repeated small meals from their hosts to support production of their batches of eggs. Both females and males feed only on blood. Cattle and domestic buffalo are also the main hosts of Stomoxys and Haematobia flies. Irritation is caused by large numbers of Musca house-flies, through to severe biting stress from dense populations of Stomoxys or Haematobia flies. Musca house-flies, face-flies, and similar types transmit

6785-638: The Netherlands, then Belgium, Germany, and Luxembourg. In 2007, the first case of bluetongue in the Czech Republic was detected in one bull near Cheb at the Czech-German border. In September 2007, the UK reported its first ever suspected case of the disease, in a Highland cow on a rare-breeds farm near Ipswich, Suffolk . Since then, the virus has spread from cattle to sheep in Britain. By October 2007, bluetongue had become

6900-401: The U.S., and 22% of the total U.S. methane emissions . The meat from domestically raised ruminants has a higher carbon equivalent footprint than other meats or vegetarian sources of protein based on a global meta-analysis of lifecycle assessment studies. Methane production by meat animals, principally ruminants, is estimated 15–20% global production of methane, unless the animals were hunted in

7015-508: The US, Africa, the Middle East, Asia, and Europe. An outline of the transmission cycle of BTV is illustrated in article Parasitic flies of domestic animals . Its occurrence is seasonal in the affected Mediterranean countries, subsiding when temperatures drop and hard frosts kill the adult midge vectors . Viral survival and vector longevity is seen during milder winters. A significant contribution to

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7130-442: The ability to hydrolyse the beta [1–4] glycosidic bond of plant cellulose due to the lack of the enzyme cellulase . Thus, ruminants completely depend on the microbial flora, present in the rumen or hindgut, to digest cellulose. Digestion of food in the rumen is primarily carried out by the rumen microflora, which contains dense populations of several species of bacteria , protozoa , sometimes yeasts and other fungi – 1 ml of rumen

7245-419: The abomasum. This is the gastric compartment of the ruminant stomach. The abomasum is the direct equivalent of the monogastric stomach, and digesta is digested here in much the same way. This compartment releases acids and enzymes that further digest the material passing through. This is also where the ruminant digests the microbes produced in the rumen. Digesta is finally moved into the small intestine , where

7360-516: The absorption of nutrients by reducing the populations of proteolytic rumen bacteria. Very high levels of tannin intake can produce toxicity that can even cause death. Animals that normally consume tannin-rich plants can develop defensive mechanisms against tannins, such as the strategic deployment of lipids and extracellular polysaccharides that have a high affinity to binding to tannins. Some ruminants (goats, deer, elk, moose) are able to consume food high in tannins (leaves, twigs, bark) due to

7475-587: The adult females fly actively to seek out only these hosts on which to lay their eggs. Adults are large flies, and unusual amongst brachyceran flies because they have a dense covering of fine setae (like hairs) and colored patterns that make them appear like bumble-bees (Hymenoptera). All species of the Oestridae are so highly adapted to the myiasis type of parasitism that the adults do not feed and have only residual mouthparts (see photograph of Hypoderma iparece ). All these flies have an obligate myiasis life-cycle, with

7590-463: The assumption that feeding habits in ruminants cause morphological differences in their digestive systems, including salivary glands, rumen size, and rumen papillae. However, Woodall found that there is little correlation between the fiber content of a ruminant's diet and morphological characteristics, meaning that the categorical divisions of ruminants by Hofmann and Stewart warrant further research. Also, some mammals are pseudoruminants , which have

7705-486: The available vaccines, though, precludes later serological monitoring of affected cattle populations, a problem that could be resolved using next-generation subunit vaccines. In January 2015, Indian researchers launched a vaccine named Raksha Blu that is designed to protect livestock against five strains of the bluetongue virus prevalent in the country. Although bluetongue disease was already recognized in South Africa in

7820-499: The body into head, thorax, and abdomen with distinct segmentation of the thorax and abdomen. The thorax contains large blocks of muscle that power the single pair of wings. Digestive and reproductive organs fill the abdomen. Also unique to the Diptera is a pair of halteres (derived from wings during evolution) that aid agile flight by these flies. Mosquitoes have veined and scaled wings, long legs, and long hypodermic mouthparts sheathed in

7935-447: The cecotropes. The primary difference between ruminants and nonruminants is that ruminants' stomachs have four compartments: The first two chambers are the rumen and the reticulum. These two compartments make up the fermentation vat and are the major site of microbial activity. Fermentation is crucial to digestion because it breaks down complex carbohydrates, such as cellulose, and enables the animal to use them. Microbes function best in

8050-459: The cell with VP2, triggering receptor-mediated endocytosis of the virus. The low pH within the endosome then triggers BTV's membrane penetration protein VP5 to undergo a conformational change that disrupts the endosomal membrane. Uncoating yields a transcriptionally active 470S core particle which is composed of two major proteins VP7 and VP3, and the three minor proteins VP1, VP4 and VP6 in addition to

8165-400: The digestion and absorption of nutrients occurs. The small intestine is the main site of nutrient absorption. The surface area of the digesta is greatly increased here because of the villi that are in the small intestine. This increased surface area allows for greater nutrient absorption. Microbes produced in the reticulorumen are also digested in the small intestine. After the small intestine is

8280-426: The dsRNA genome. There is no evidence that any trace of the outer capsid remains associated with these cores, as has been described for reovirus. The cores may be further uncoated to form 390S subcore particles that lack VP7, also in contrast to reovirus. Subviral particles are probably akin to cores derived in vitro from virions by physical or proteolytic treatments that remove the outer capsid and causes activation of

8395-484: The early Miocene . Ruminantia is a crown group of ruminants within the order Artiodactyla , cladistically defined by Spaulding et al. as "the least inclusive clade that includes Bos taurus (cow) and Tragulus napu (mouse deer)". Ruminantiamorpha is a higher-level clade of artiodactyls, cladistically defined by Spaulding et al. as "Ruminantia plus all extinct taxa more closely related to extant members of Ruminantia than to any other living species." This

8510-514: The early 19th century, a comprehensive description of the disease was not published until the first decade of the 20th century. In 1906, Arnold Theiler showed that bluetongue was caused by a filterable agent. He also created the first bluetongue vaccine, which was developed from an attenuated BT V strain. For many decades, bluetongue was thought to be confined to Africa. The first confirmed outbreak outside of Africa occurred in Cyprus in 1943. In 2021,

8625-427: The esophagus to finally reach the stomach. The final larval stage is completed with the larvae attached to the mucosa of the horse's stomach. When ready to pupate the larvae detach and are voided in the horse's feces. Another example is Dermatobia hominis , torsalo-fly, which is an important parasite of cattle, and sometimes humans, in tropical regions of South America. The larvae cause a localized, furuncular (= like

8740-434: The feeding activity of the flies is described here under parasitic disease. Disease caused by small pathogenic organisms that pass from the flies to domestic animals is described here under transmitted organisms; prominent examples are provided from the many species. Disease caused by the feeding activity of dipteran flies is described here under parasitic disease . Disease caused by small pathogenic organisms that pass from

8855-432: The females lay their eggs on the same dead animal material and the larvae feed their by rasping at the muscle and other tissues with their mouthparts. However, species of Lucilia and some other genera may opportunistically invade the tissues of live hosts, such as sheep or cattle and feed there parasitically. Other genera such as Chrysomya , Cochliomyia and Wohlfahrtia are specifically adapted for this type of feeding by

8970-803: The fetal immune system is fully developed, may result in a chronic infection that lingers until the first months after birth of the lamb. Midges then spread the pathogen from the calves to other animals, starting a new season of infection. Prevention is effected via quarantine , inoculation with live modified virus vaccine , and control of the midge vector , including inspection of aircraft. Protection by live attenuated vaccines (LAVs) are serotype specific. Multiserotype LAV cocktails can induce neutralizing antibodies against unincluded serotypes, and subsequent vaccinations with three different pentavalent LAV cocktails induce broad protection. These pentavalent cocktails contain 15 different serotypes in total: serotypes 1 through 14, as well as 19. Immunization with any of

9085-517: The financial costs of these diseases are high. These problems occur wherever domestic animals are reared. This article provides an overview of parasitic flies from a veterinary perspective, with emphasis on the disease-causing relationships between these flies and their host animals. The article is organized following the taxonomic hierarchy of these flies in the phylum Arthropoda , order Insecta . Families and genera of dipteran flies are emphasized rather than many individual species. Disease caused by

9200-428: The flies to domestic animals is described here under transmitted organisms ; these organisms are often of numerous species thus only prominent examples are provided. Feeding by adult flies may cause irritation through acute stress from painful bites, resulting in loss of grazing time and reduced gain in weight. Feeding by adult flies on the blood of their hosts exposes the hosts to pathogenic organisms that are infecting

9315-417: The fly, this can lead to acute disease of the host's blood and other organs. Feeding by adult flies using their sponging mouthparts can also expose the hosts to pathogenic organisms that have contaminated the mouthparts. Larvae of some flies are adapted to feed on the tissues of their host, causing direct pathological damage to organs; this is known as myiasis . (Note that the former suborder Cyclorrhapha

9430-782: The front part of the digestive system and therefore is called foregut fermentation , typically requires the fermented ingesta (known as cud ) to be regurgitated and chewed again. The process of rechewing the cud to further break down plant matter and stimulate digestion is called rumination . The word "ruminant" comes from the Latin ruminare , which means "to chew over again". The roughly 200 species of ruminants include both domestic and wild species. Ruminating mammals include cattle , all domesticated and wild bovines , goats , sheep , giraffes , deer , gazelles , and antelopes . It has also been suggested that notoungulates also relied on rumination, as opposed to other atlantogenatans that rely on

9545-500: The gene segments during co-infection of the host cell. Reassortment can lead to a rapid shift in phenotypes independent of the slow rate of mutation. During this process, gene segments are not randomly reassorted. Rather, there appears to be a mechanism for selecting for or against certain segments from the parental serotypes present. However, this selective mechanism is still poorly understood. Bluetongue has been observed in Australia,

9660-435: The general habitat, some species of brachyceran flies are parasitic in their larval stage whilst the adults that develop from these larvae are non-parasitic. This parasitism by brachyceran larvae causes the disease myiasis . Some of the brachyceran flies are important transmitters of pathogenic organisms through a route known as mechanical (or contaminative) transmission. These flies have complex cutting mouthparts that make

9775-472: The genus Stephanofilaria to the skin of cattle, causing stephanofilariasis , a suppurating dermatitis known as hump sore. Stomoxys flies transmit the bacterium Eperythrozoon ovis to sheep and this infection may lead to fever and anemia. There is one genus in this Family: Glossina , known as tsetse-flies or simply tsetse. Flies of this family are similar to Stomoxys flies within the Muscidae, but have

9890-445: The genus Calliphora can be significant as transmitters of various bacteria involved in mastitis of cattle. The conjunctivitis of cattle known as pink-eye is caused by Moraxella bovis bacteria and may be transmitted by blow-flies. Typical genera are Hypoderma , Gasterophilus , Dermatobia and Oestrus (fly) . Oestrid flies at their larval stage tend to be adapted to feed on a few closely related species of host animal and

10005-400: The hosts may be caused and there are production losses from reduction of value of cattle hides, and reduced grazing time by sheep. Harm to cattle may be caused through panic (known as gadding) at the approach of the flies if that leads to traumatic injury. There are no organisms of known importance transmitted by oestrid flies. Genera of importance are Melophagus and Hippobosca . This is

10120-486: The infected horses during an epidemic. Epizootic hemorrhagic disease virus is closely related and crossreacts with Bluetongue virus on many blood tests. Ruminants Ruminants are herbivorous grazing or browsing artiodactyls belonging to the suborder Ruminantia that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The process, which takes place in

10235-412: The infection can slowly develop into a multi-organ stage with fatal consequences. The typical genus is Simulium , but also Cnephia and Austrosimulium are locally important. These are medium nematocerans, halfway in size between mosquitoes and midges. The body is compact, wings are clear except for veins close to leading edge, and antennae are short with compact segments appearing like rings. Thorax

10350-399: The insecticide, or in automatic walk-through sprayers. The same types of insecticides are also formulated into the plastic sheet of ear tags for protecting cattle against Musca and similar flies feeding around the head of cattle. Insect growth regulators (juvenile hormones, chitin synthesis inhibitors, etc.) are available. For example, the insect growth regulator cyromazine is effective for

10465-418: The large intestine. The major roles here are breaking down mainly fiber by fermentation with microbes, absorption of water (ions and minerals) and other fermented products, and also expelling waste. Fermentation continues in the large intestine in the same way as in the reticulorumen. Only small amounts of glucose are absorbed from dietary carbohydrates. Most dietary carbohydrates are fermented into VFAs in

10580-512: The larvae. When larvae of Lucilia feed parasitically they cause the disease facultative myiasis (facultative = opportunistic or optional). When this occurs on sheep it is often known as blow-fly strike. This causes severe distress to the host and may be fatal due to toxemia from ammonia excreted by masses of infesting larvae. Females of Chrysomya , Cochliomyia and Wohlfahrtia and similar genera always seek out their host such as cattle, sheep, dogs, to lay their eggs at vulnerable sites such as

10695-623: The leaf, bud, seed, root, and stem tissues, tannins are widely distributed in many different species of plants. Tannins are separated into two classes: hydrolysable tannins and condensed tannins . Depending on their concentration and nature, either class can have adverse or beneficial effects. Tannins can be beneficial, having been shown to increase milk production, wool growth, ovulation rate, and lambing percentage, as well as reducing bloat risk and reducing internal parasite burdens. Tannins can be toxic to ruminants, in that they precipitate proteins, making them unavailable for digestion, and they inhibit

10810-427: The lifecycle feed on blood. Typical genera are Culex , Aedes , and Anopheles The basic structure of dipteran flies is illustrated in the diagram. Veterinary parasitology also covers arthropods in the class Acari , the ticks of domestic animals , and mites of livestock , which have distinctly different structure from arthropods in the class Insecta. However, flies in the order Diptera show clear division of

10925-478: The mild winters of the temperate zone. Some midges may even move indoors to avoid the cold temperature of the winter. Additionally, BTV could cause a chronic or latent infection in some animals, providing another means for BTV to survive the winter. BTV can also be transmitted from mother to fetus. The outcome is abortion or stillbirth if fetal infection occurs early in gestation and survival if infection occurs late. However infection at an intermediate stage, before

11040-510: The more typical hindgut fermentation , though this is not entirely certain. Ruminants represent the most diverse group of living ungulates . The suborder Ruminantia includes six different families: Tragulidae , Giraffidae , Antilocapridae , Cervidae , Moschidae , and Bovidae . The first fossil ruminants appeared in the Early Eocene and were small, likely omnivorous, forest-dwellers. Artiodactyls with cranial appendages first occur in

11155-414: The neck ( opisthotonos or torticollis ) is observed in severely affected animals. Not all animals develop signs, but all those that do lose condition rapidly, and the sickest die within a week. For affected animals that do not die, recovery is very slow, lasting several months. The incubation period is 5–20 days, and all signs usually develop within a month. The mortality rate is normally low, but it

11270-551: The northward spread of bluetongue disease has been the ability of C. obsoletus and C.pulicaris to acquire and transmit the pathogen, both of which are spread widely throughout Europe. This is in contrast to the original C.imicola vector, which is limited to North Africa and the Mediterranean. The relatively recent novel vector has facilitated a far more rapid spread than the simple expansion of habitats north through global warming. In August 2006, cases of bluetongue were found in

11385-666: The obligate myiasis type, it is possible to colonize the entire lifecycle in large factory conditions. Massive numbers of pupae are sterilized by irradiation. When released, these flies mate with the wild flies and the matings produce no offspring. The reproductive rate of the wild flies can be reduced to the level of eradication. Eradication schemes are being extended in the Americas. Infections with Trypanosoma species are treated, either prophylactically or to treat acute cases with synthetic chemical drugs such as diminazine . Infections with nematode worms causing filariosis may be treated with

11500-475: The only stage of tick seen with three pairs of legs will be larvae these are much smaller than louse-flies. Adults of the genus Hippobosca are large, robust flies that retain their wings to fly for repeated blood meals, between hosts such as cattle, camels or horses in a herd. Stout piercing mouthparts project downward from the head (see Hippobosca in Gallery). The abdomen bulges largely, especially when containing

11615-460: The particle size. Smaller particle size allows for increased nutrient absorption. Fiber, especially cellulose and hemicellulose , is primarily broken down in these chambers by microbes (mostly bacteria , as well as some protozoa , fungi , and yeast ) into the three volatile fatty acids (VFAs): acetic acid , propionic acid , and butyric acid . Protein and nonstructural carbohydrate ( pectin , sugars , and starches ) are also fermented. Saliva

11730-430: The plants and the cycle begins once again. In essence, the methane belched from cattle is not adding new carbon to the atmosphere. Rather it is part of the natural cycling of carbon through the biogenic carbon cycle . In 2010, enteric fermentation accounted for 43% of the total greenhouse gas emissions from all agricultural activity in the world, 26% of the total greenhouse gas emissions from agricultural activity in

11845-560: The presence in their saliva of tannin-binding proteins. The Law of Moses in the Bible allowed the eating of some mammals that had cloven hooves (i.e. members of the order Artiodactyla ) and "that chew the cud", a stipulation preserved to this day in Jewish dietary laws . The verb 'to ruminate' has been extended metaphorically to mean to ponder thoughtfully or to meditate on some topic. Similarly, ideas may be 'chewed on' or 'digested'. 'Chew

11960-416: The prevention or treatment of infestations with blowfly larvae. Botanical extracts such as azadirachtin from the neem tree can be formulated as repellents and insecticides, with the potential advantage of more rapid degradation to harmless forms in the environment, lower toxicity and potentially lower cost. These can contribute to control of blowflies and tsetse-flies for example. The blowfly traps contain

12075-614: The protozoan Trypanosoma evansi that causes in camels and horses the disease called surra . These flies also transmit the protozoan T.vivax that causes in cattle the disease called nagana . Tabanid flies are also transmitters the bacteria Anaplasma marginale and A.centrale to cattle, sheep and goats, causing anaplasmosis . Typical genera are Musca , Hydrotaea , Stomoxys and Haematobia . These are medium to large flies of compact structure, with clear wings of complex venation. Antennae are highly characteristic with antennae consisting of several compact segments that lie in

12190-408: The reticulorumen. The degraded digesta, which is now in the lower liquid part of the reticulorumen, then passes into the next chamber, the omasum. This chamber controls what is able to pass into the abomasum. It keeps the particle size as small as possible in order to pass into the abomasum. The omasum also absorbs volatile fatty acids and ammonia. After this, the digesta is moved to the true stomach,

12305-541: The rumen, they consume about 10% of the carbon, 60% of the phosphorus, and 80% of the nitrogen that the ruminant ingests. To reclaim these nutrients, the ruminant then digests the bacteria in the abomasum . The enzyme lysozyme has adapted to facilitate digestion of bacteria in the ruminant abomasum. Pancreatic ribonuclease also degrades bacterial RNA in the ruminant small intestine as a source of nitrogen. During grazing, ruminants produce large amounts of saliva – estimates range from 100 to 150 litres of saliva per day for

12420-646: The rumen. The glucose needed as energy for the brain and for lactose and milk fat in milk production, as well as other uses, comes from nonsugar sources, such as the VFA propionate, glycerol, lactate, and protein. The VFA propionate is used for around 70% of the glucose and glycogen produced and protein for another 20% (50% under starvation conditions). Wild ruminants number at least 75 million and are native to all continents except Antarctica and Australia. Nearly 90% of all species are found in Eurasia and Africa. Species inhabit

12535-466: The skin of animals at risk. This is usually done with a pour-on applicator along the back line of the host from where the insecticide spreads downwards through the hair coat. In addition, to protect against flies such as Stomoxys and Glossina species that feed on legs and belly the insecticide can be sprayed selectively to those regions. Also, cattle can be treated using self-applicators such as back-rubbers made of large bundles of fiber impregnated with

12650-449: The south of Norway showed an immune response to bluetongue. Norway was declared free of the disease in 2011. As of November 2023, cases of bluetongue have been recorded in Belgium, Germany, the Netherlands, France, Spain, and the UK. Although the disease is not a threat to humans, the most vulnerable common domestic ruminants are cattle, goats, and especially, sheep. A puzzling aspect of BTV

12765-497: The state where the organism is at an infective stage of its lifecycle. The repeated cycles of egg laying and feeding of the female fly (= gonotrophic cycle) provides the opportunity for the transmitted organisms to develop, multiply, and be exposed to further vertebrate hosts where they can complete their lifecycle. Only the adult flies are involved in this biological transmission, in contrast to biological transmission by other arthropods such as lice or ticks in which all active stages of

12880-431: The tongue its typical blue appearance, though this sign is confined to a minority of the animals. Nasal signs may be prominent, with nasal discharge and stertorous respiration. Some animals also develop foot lesions, beginning with coronitis, with consequent lameness. In sheep, this can lead to knee-walking. In cattle, constant changing of position of the feet gives bluetongue the nickname the dancing disease . Torsion of

12995-421: The upper gastric tract and stomach of horses and other equids. Larval Hypoderma warble-flies infest the skin and muscles of cattle. Larval Oestrus nasal-bots infest the nasal cavities of sheep and goats. In the case of stomach-bots it is often uncertain how much clinical disease or loss of production small levels of infestation causes the host. With infestations of warble-flies and nasal-bots severe distress to

13110-453: The ventilation slats or windows of housing for livestock animals. The fiber netting can be impregnated with insecticides such as the synthetic pyrethroid deltamethrin that acts rapidly when flies such as Stomoxys or Glossina species land on it. Valuable horses in areas infested with Culicoides midges or Simulium black-flies can be protected with commercially available shields made of cloth that fit over head, neck and back. Flies such as

13225-717: The wild. The current U.S. domestic beef and dairy cattle population is around 90 million head, approximately 50% higher than the peak wild population of American bison of 60 million head in the 1700s, which primarily roamed the part of North America that now makes up the United States. Parasitic flies of domestic animals Many species of flies of the two-winged type, Order Diptera , such as mosquitoes, horse-flies, blow-flies and warble-flies, cause direct parasitic disease to domestic animals, and transmit organisms that cause diseases. These infestations and infections cause distress to companion animals, and in livestock industry

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